Medical and surgical implants are placed often in anatomic spaces where it is desirable for the implant to conform to the unique anatomy of the targeted anatomic space and secure a seal therein, preferably without disturbing or distorting the unique anatomy of that targeted anatomic space.
While the lumens of most hollow anatomic spaces are ideally circular, in fact, the cross-sectional configurations of most anatomic spaces are, at best, ovoid, and may be highly irregular. Such lumenal irregularity may be due to anatomic variations and/or to pathologic conditions that may change the shape and topography of the lumen and its associated anatomic wall. Examples of anatomic spaces where such implants may be deployed include, but are not limited to, blood vessels, the heart, other vascular structures, and vascular defects (such as thoracic and abdominal aortic aneurysms).
For a patient to be a candidate for existing endograft methods and technologies, to permit an adequate seal, a proximal neck of, ideally, at least 12 mm of normal aorta must exist downstream of the left subclavian artery for thoracic aortic aneurysms or between the origin of the most inferior renal artery and the origin of the aneurysm in the case of abdominal aneurysms. Similarly, ideally, at least 12 mm of normal vessel must exist distal to the distal extent of the aneurysm for an adequate seal to be achieved. The treatment of Aortic Stenosis through Transcather Aortic Valve Replacement (TAVR) is becoming more common. The limitations of current TAVR techniques do not allow for repositioning of the implant once it has been deployed in place. Further, the final expanded diameter of the current devices is fixed making pre-sizing a critical and difficult step.
Migration of existing endografts has also been a significant clinical problem, potentially causing leakage and profusion of aneurysms and/or compromising necessary vascular supplies to arteries such as the coronary, carotid, subclavian, renal, or internal iliac vessels. This problem only has been addressed partially by some existing endograft designs, in which barbs or hooks have been incorporated to help retain the endograft at its intended site. However, most existing endograft designs are solely dependent on radial force applied by varying length of stent material to secure a seal against the recipient vessel walls.
Because of the limitations imposed by existing vascular endograft devices and endovascular techniques, a significant number of abdominal and thoracic aneurysms repaired in the U.S. are still managed though open vascular surgery, instead of the lower morbidity of the endovascular approach.
Pre-sizing is required currently in all prior art endografts. Such pre-sizing based on CAT-scan measurements is a significant problem. This leads, many times, to mis-sized grafts. In such situations, more graft segments are required to be placed, can require emergency open surgery, and can lead to an unstable seal and/or migration. Currently there exists no endograft that can be fully repositioned after deployment.
Thus, a need exists to overcome the problems with the prior art systems, designs, and processes as discussed above.